KAFKA-20987: Remove hamcrest from org.apache.kafka.streams.processor.internals.metrics package

[shantanushukla]

JIRA: https://issues.apache.org/jira/browse/KAFKA-20987
Parent: https://issues.apache.org/jira/browse/KAFKA-20948

Migrate hamcrest assertThat usage in org.apache.kafka.streams.processor.internals.metrics tests to JUnit 5. This package is not covered by the existing subtasks:

• KAFKA-20963 / PR KAFKA-20963: Remove hamcrest from org.apache.kafka.streams.processor #23200 covers only org.apache.kafka.streams.processor (top-level)
• KAFKA-20965 / PR KAFKA-20965: Remove hamcrest from org.apache.kafka.streams.state.internals.metrics package #23201 covers org.apache.kafka.streams.state.internals.metrics

Files changed:

• ProcessorNodeMetricsTest.java
• StreamsMetricsImplTest.java
• TaskMetricsTest.java
• ThreadMetricsTest.java
• TopicMetricsTest.java

No production code changes. This contribution is original work and is licensed to the project under the Apache License, Version 2.0.

Tests

./gradlew :streams:test \
  --tests org.apache.kafka.streams.processor.internals.metrics.ProcessorNodeMetricsTest \
  --tests org.apache.kafka.streams.processor.internals.metrics.StreamsMetricsImplTest \
  --tests org.apache.kafka.streams.processor.internals.metrics.TaskMetricsTest \
  --tests org.apache.kafka.streams.processor.internals.metrics.ThreadMetricsTest \
  --tests org.apache.kafka.streams.processor.internals.metrics.TopicMetricsTest \
  :streams:checkstyleTest :streams:spotlessCheck

BUILD SUCCESSFUL.

Reviewers: Chia-Ping Tsai chia7712@gmail.com

[chia7712]

LGTM